The end of one era, the beginning of another

I thought I was getting a new Macintosh PC. Instead, the box said "Quad Xeon 64-bit workstation." It was then that it really hit me—the Big Switch was over and my once shiny Power Macintosh G5 was yesterday's news.

The introduction of the new, yet familiar-looking Mac Pro at the Worldwide Developers Conference (along with the updated Xserve) closed the book on the PowerPC's 12-year run in Apple's product lineup. And it all happened so fast. Just last year, Apple CEO Steve Jobs stood in front of the gathered masses and dropped the big bombshell.

Apple's initial timeframe was conservative. The first Intel system would ship by June 6, 2006, with the transition complete sometime in 2007. Instead, Apple was able to accelerate its schedule, unveiling the first two Intel Macs at Macworld San Francisco this past January. The iMac Core Duo and MacBook Pro were joined by the Mac mini in March and the MacBook in May.

Making the transition easier for Apple was Intel's new Core Duo chip. Available at the beginning of 2006, Yonah (aka, Core Duo) was a good fit across much of Apple's product line, with two notable exceptions: the Xserve and Power Macintosh. Both of those needed something beefier than a 32-bit processor and thanks to Intel's roadmap, we all knew what it was and when it would be coming. Sure enough, Jobs delivered the goods at the WWDC keynote

Tech specs

The Xeon 5100 series

Better known by its code name Woodcrest, the Xeon 5100 series provides the brains for Apple's new Mac Pro towers. Although it shares a name with Intel's longstanding server-centric CPU, the 5100s are different beasts from their Netburst predecessors. They are built on the same Core architecture as Merom (Core 2 Duo) laptop CPUs and the just-released desktop CPU Conroe (also Core 2 Duo).

Apple is using three Xeons across the Mac Pro line: the 5130 (2.0GHz), 5150 (2.66GHz), and the 5160 (3.0GHz). The default configuration for the Mac Pro uses Van Halen's favorite CPU, the Xeon 5150, with the 5130 and 5160 available as build-to-order options for $300 less and $800 more, respectively. Since the machine being reviewed has the 5150, I'll just touch on that processor. However, the CPUs are identical except for the speed. A detailed look at the Xeon architecture is outside the scope of this review, but we can hit a few of the highlights of the 5150.

Introduced in June, the Xeon 5100 series is a 64-bit CPU intended primarily for use in servers and high-performance workstations. In fact, Intel prefers that vendors using the Xeon in desktop computers call them "workstations" rather than "PCs," hence the prominent "64-bit workstation" labeling on the box.

Like the other Core and Core 2 processors, the Xeon 5150 is fabricated using a 65nm process. It's also a dual-core chip, which is why Apple refers to the Mac Pro as a "Quad Xeon": two CPUs, four cores. Each 5150 has 4MB of L2 cache which is shared between the two cores. The Mac Pro also features 1333MHz, 64-bit dual independent frontside buses, meaning that each Xeon has its own dedicated bus to the northbridge.

When it comes to heat, the Xeon 5150 runs cooler than its Netburst predecessors. It has a thermal design power of 65 watts (the 5160 has a TDP of 80W), which is a big improvement over its predecessor's 135W TDP. IBM has not released the TDP figures for the PowerPC 970MP powering the last G5s, so a direct comparison is impossible. Keep in mind that whatever the figure, it was high enough to require liquid cooling.